One of our readers, Stanley, posted this comment to the dead body story earlier, and it was so good I thought I'd repost it here.

Thanks Stanley!

Here’s a follow-up to “dead body” experience from the Sacramento  
River. I was a fisheries biologist who worked for the US Forest  
Service research branch in Boise, Idaho. Snorkeling is a common  
method of quantifying fish populations. It’s particularly effective  
in the winter when the water is low and clear. You can spot the fish  
and count them well. And, of course, you need a very good, well  
insulated wet suit. 

Here’s a related story you might enjoy. My colleague at the USFS in  
Boise, Craig, did his Master’s thesis at Idaho State U and his  
research was up in Island Park, ID, near Yellowstone. Craig’s  
research was to assess winter kill of trout during extremely cold  
temperatures. Like the researcher you observed, Craig would dawn a  
wetsuit and swim the mountain streams in the dead of winter, but  
Craig’s major professor required his students to do their snorkeling  
and fish counts at night and with flashlights. 

One particularly cold night in the remote Idaho mountains, Craig  
finished his fish counts about 3:00 a.m. It was 10 degrees outside  
with a chill factor below zero. Craig was walking back to his car  
about 1/4 mile upstream, going across a snow-covered meadow. It was  
so brutally cold he kept his wetsuit, mask, and swim fins on just to  
stay as warm as he could. The nearby highway was deserted until a  
lone trucker drove by and slowed way down. Craig waved at the  
trucker, who immediately hit the gas pedal for all it was worth and  
gunned his truck out of there. No doubt the trucker thought he saw  
Bigfoot! Craig fears he scared the wits out of the poor guy. :-) 

So clearly, fisheries biologists who do snorkeling are the source of  
all kinds of confusion!